Technology Roadmap: Energy Storage

Energy storage technologies are valuable components in most energy systems and could be an important tool in achieving a low-carbon future. These technologies allow for the decoupling of energy supply and demand, in essence providing a valuable resource to system operators. There are many cases where energy storage deployment is competitive or near-competitive in today’s energy system. However, regulatory and market conditions are frequently ill-equipped to compensate storage for the suite of services that it can provide. Furthermore, some technologies are still too expensive relative to other competing technologies (e.g. flexible generation and new transmission lines in electricity systems).

One of the key goals of this new roadmap is to understand and communicate the value of energy storage to energy system stakeholders. This will include concepts that address the current status of deployment and predicted evolution in the context of current and future energy system needs by using a “systems perspective” rather than looking at storage technologies in isolation.

Key Findings

Energy storage technologies are valuable in most energy systems, with or without high levels of variable renewable generation. Today, some smaller-scale systems are cost competitive or nearly competitive in remote community and off-grid applications. Large-scale thermal storage technologies are competitive for meeting heating and cooling demand in many regions.

Individual storage technologies often have the ability to supply multiple energy and power services. The optimal role for energy storage varies depending on the current energy system landscape and future developments particular to each region.

To support electricity sector decarbonisation in the Energy Technology Perspectives (ETP) 20142DS, an estimated 310 GW of additional grid-connected electricity storage capacity would be needed in the United States, Europe, China and India. Significant thermal energy storage and off-grid electricity storage potential also exists. Additional data are required to provide a more comprehensive assessment and should be prioritised at the national level.

Market design is key to accelerating deployment. Current policy environments and market conditions often cloud the cost of energy services, creating significant price distortions and resulting in markets that are ill-equipped to compensate energy storage technologies for the suite of services that they can provide.

Public investment in energy storage research and development has led to significant cost reductions. However, additional efforts (e.g. targeted research and development investments and demonstration projects) are needed to further decrease energy storage costs and accelerate development.

Thermal energy storage systems appear well-positioned to reduce the amount of heat that is currently wasted in the energy system. This waste heat is an underutilised resource, in part because the quantity and quality of both heat resources and demand is not fully known.

Energy Technology Perspectives 2014 vision for electricity storage

The vision presented in this roadmap is that of electricity storage in the 2DS of ETP 2014. Due to data and modelling capability constraints, this vision is limited to the use of four categories of grid-connected electricity storage technologies13 for supplying daily energy storage needs in China, India, the European Union and the United States, where load-levelling applications help optimise the high penetration of variable renewable generation.

This limited 2DS vision does not imply a lack of large-scale potential for thermal energy storage technologies nor for other electricity storage systems, including those for application in remote communities and off-grid. Rather, it illustrates the need to establish international and national data co-operation to support more comprehensive global energy storage potential assessments, foster energy storage research, monitor progress, and assess R&D bottlenecks.

The ETP 2014 publication explores the future role of daily electricity storage technologies under a range of sensitivities regarding future costs and performance of storage and competing technologies, including flexible thermal power generation and to some extent, demand response. Three of these variants are reproduced in this roadmap:

the 2°C Scenario (2DS)

a "breakthrough" scenario, with aggressive cost reductions in storage technologies

an "EV" scenario, where demand response from "smart" charging of the electric vehicle fleet in the 2DS provides additional flexibility to the system